Patients meeting DSM-III-R criteria for social phobia are evaluated using psychological, physiological, biochemical and pharmacotherapeutic methodologies. In the past year, the study has developed along three complementary themes: 1) descriptive, 2) neuroendocrine correlates, and 3) differential medication responses. 1) Descriptive: Social phobia can be reliably distinguished from panic disorder on the basis of a few widely used rating scales. A discriminant function analysis has yielded an algorithm which can correctly diagnose subjects 80% of the time. These syndromes differ in lifetime rates of major depression as well as age of onset and sex-distribution. 2) Neuroendocrine Correlates: Particular attention has been paid to the functional integrity of the noradrenergic neurotransmitter system in patients with social phobia compared with panic disorder patients and healthy volunteers. Patients with social phobia have evidence for noradrenergic dysfunction. 3) Differential Medication Responses: Further analysis of the double-blind treatment study (phenelzine vs. alprazolam vs. placebo) reveals that phenelzine is significantly superior to alprazolam and placebo when unequivocal response is measured (delta in FQ-SP subscale to level below mean for general population). A pilot study has been initiated to test the relative efficacy of imipramine versus phenelzine in the treatment of social phobia. We have also initiated an open study to obtain preliminary information regarding the usefulness of fluoxetine in the treatment of social phobia.